1. Field of the Invention
The present invention relates to a mobile communication terminal and corresponding method in which information is provided to the mobile terminal when a handoff request is rejected.
2. Discussion of the Related Art
Generally, a mobile terminal enables a large amount of data to be exchanged with a base station at high speed via a portable Internet. Communication specifications for the portable Internet include World Interoperability for Microwave Access (hereinafter abbreviated WiMAX), Wireless Broadband (hereinafter abbreviated WiBro), etc.
WiMAX is a technical specification developed by providers in the WiMAX Forum. Further, WiMAX compensates the wireless LAN technology by considerably extending the Internet-available range outside of buildings. WiBro is a wireless portable Internet solution developed by the Ministry of Information and Communication Republic of Korea, the Telecommunication Technology Association (TTA) and mobile communication providers. WiBro provides an ultra-high-speed Internet service for portable terminals.
Therefore, using the portable Internet service, a portable device such as a handset, a laptop, a personal portable information terminal, a PDA (personal digital assistant), a smart phone, etc. can access the Internet. In addition, to stably exchange data with a prescribed base station via the portable Internet, the mobile communication terminal frequently scans neighboring base stations and performs a handover process via a specific one of the neighboring base stations according to a corresponding scanning result.
For instance, if a received signal strength of a serving base station currently transmitting/receiving data falls below a predetermined value, or if it is necessary for the mobile terminal to move into a neighboring base station providing a higher received signal strength, the mobile terminal decides to perform the handover process and executes a handover negotiation procedure with the serving base station.
In more detail, a handover procedure according to a related art will now be explained with reference to FIG. 7. As shown in FIG. 7, a mobile communication terminal 710 first transmits a handover request message requesting a handover to another base station to the serving base station 720 (S740) The message includes information about a target base station 730.
The serving base station 720 then transmits a handover response message in response to the handover request message to the mobile terminal 710 (S750). The handover response message may be an instruction message that allows the handover request or may be a rejection message that rejects the handover request. Further, the handover response message includes information about a target base station recommended by the serving base station 720.
When the handover response message is the instructing message for instructing the handover, the mobile terminal 710 transmits a handover confirmation message indicating information about a final target base station to the serving base station 720 (S760). Subsequently, the mobile terminal 710 executes the handover process to the final target base station 730 (S770).
However, when the handover response message is a rejection message rejecting the handover request, the mobile terminal 710 arbitrarily decides what next action to take corresponding to the handover rejection and then performs the decided action. Thus, the related art handover method has the following problems or disadvantages.
Firstly, when the handover request is rejected, the mobile terminal arbitrarily decides the next action to take. That is, the terminal does not consider a current network status, but rather arbitrarily decides what next action to perform. Therefore, the mobile communication terminal does not perform an optimal action suitable for a network environment to correspond to the handover rejection.
Secondly, because the mobile terminal is unable to determine a reason for the handover rejection in association with a network environment, the terminal performs a next action for the handover rejection regardless of the current network environment. Thirdly, when the handover request is rejected, the terminal only receives the rejection instruction message, but does not receive any detailed information about the handover rejection.